Exposure meter and camera setting



May 11, 1954 G. N. SMITH 2,677,999

ExPosUEE METER AND CAMERA SETTING MECHANISM Original Filed Feb. 2, 19495 Sheets-Shel?. l

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I '2. al n Y fo?, I u I 97 INVENToR. Gana/azz 5m/'2% May 11, 1954 G; N.SMITH EXPOSURE METER AND CAMERA SETTING MECHANISM 5 Sheets-Sheet 2Original Filed Feb. 2, 1949 DARK SUBJECT AVERAGE SUBJECT LIGHT SUBJECTIIIIIIIIIII||||||IIlllllllllmmllll INVENToR. Gordo/1 /V Snif/E May 11,1954 G. N. SMITH EXPOSURE METER AND CAMERA SETTING MECHANISM 5Sheets-Shee 5 Original Filed Feb. 2, 1949 May 1l, 1954 G. N. SMITH2,677,999

EXPOSURE METER AND CAMERA SETTING MECHANISM Original Filed Feb. 2, 19495 Sheets-Sheet 4 @WM-' T- *No G. N. SMITH EXPOSURE METER AND CAMERASETTING MECHANISM May 11, 1954 5 Sheets-Sheet 5 Original Filed Feb. 2,1949 Patented May 11, 1 954 UNITED STATES PATENT OFFICE EXPOSURE METERAND CAMERA SETTING MECHANISM Gordon N. Smith, Portland, Oreg., assignor,by mesne assignments, to Sawyers Inc., Progress, Oreg., a corporation ofOregon 2 Claims. 1

The present invention is an improvement in cameras comprising anexposure meter built into the camera in such manner as to set the camerafor tal-:ing proper exposures when the exposure meter is properlyadjusted.

rThis application is a division of application Serial No. 74,156, ledFebruary 2, 1949, now Patent No. 2,557,478, issued June 19, 1951.

An object of the present invention is to provide a camera with animproved exposure meter which is within the comprehension of the averagecamera user. All that the operator needs to do is to judge the type ofsubject being photographed and observe the character of the day when thephotograph is being taken. The exposure meter is so characterized thatoperation of the exposure meter sets the camera for taking properexposures.

Another object of the invention, therefore, is to provide an improvedcamera having exposure meter mechanism incorporated therein, whichmechanism replaces the diaphragm and shutter speed adjusting indicatorlevers or dials ordinarily encountered in the better types of cameras.

A further object or" the present invention is to provide a device of theforegoing type which is formed of relatively few, sturdy, inexpensiveand easily assembled parts.

The objects and advantages of the present invention will be morethoroughly understood by reference to the following specication, takenin connection with the accompanying drawings, wherein like numeralsrefer to like parts throughout.

In the drawings Fig. 1 is a plan view of a camera having the presentinvention incorporated therein, all nonessential portions of the camerabeing omitted;

Fig. 2 is an enlarged vertical section taken substantially along line 22 of Fig. 1 and illustrating the means whereby selection of the propershutter speed and diaphragm opening by means oi" the exposure metersimultaneously accomplishes the setting of the camera;

Fig. 3 is a horizontal section taken substantially along line 3-3 ofFig. 2;

Fig. 'i is a plan view of the exposure meter alone, the meter beingshown about twice its natural size;

Fig. 5 is a bottom view oi the exposure meter mechanism takensubstantially along line 5-5 of Fig. 6;

Fig. 6 is a vertical section through the exposure meter takensubstantially along line vli--IS of Fis. 4: Y

Fig. 7 is a plan view of the exposure meter illustrating one positionwhich the parts may assume;

Figs. 8 to 12, inclusive, are views similar to Fig. 7 illustrating otherpositions of the parts;

Fig. 13 is a bottom view, with parts broken away, of the exposure meterwhen formed as a separate device which may be carried upon the person;

Fig. 14 is a side View of the modiication shown in Fig. 13;

Fig. 15 is a View of one of the shutter blades of a two-blade shuttermechanism and its spring;

Fig. 16 is a view of the other shutter blade and its spring;

Fig. 17 is a partial, horizontal section through a portion of the cameraillustrating shutter speed controlling means; and

Fig. 18 is a partial View similar to Fig. 17 illustrating the means forsetting the shutters.

The invention is illustrated in Figs. 1 to 6, inclusiveas it would beembodied in a stereoscopic camera I having a pa-ir of lens assemblies IIand I2 whereby stereoscopic pairs of exposures may be taken in the usualmanner. A portion of the rear wall I3 of the camera is extended abovethe plane of the top wall I4, and an irregularly shaped, raised portionI6 oi the top wall provides, together with the portion i3, an elevatedframe ior the exposure meter mechanism. Portions of the end walls of theframe are extended upward to the level of the upper edge of the portionI3 to provide a base on which a frame plate Il is seated and retained bymeans of screws I8. A pair of indicator dials are hori- .zontal1ymounted in the space between the portion I6 and the frame plate II, theright dial constituting a shutter speed indicator 25 and the left dialconstituting a stop indicator ZI. 1t is to be appreciated that theindicators are herein illustrated in the form of manually engageable,V

rotatable indicator dials, but that other forms of movable indicatorsmay be substituted without the exercise of invention. The shutter speeddial 2) is provided with a plurality of indicia 22 adjacent which arepositioned numerals indicating the speed of the shutter in fractions ofa second, and the diaphragm indicator` dial 2l is provided with aplurality of indicia 23 adjacent which are provided the usual stopnumerals. The frame plate I'I is provided with iixed pointers 24- and 25opposite which may be positioned the selected speed or stop index,respectively. The outer edges of the dials are preferably 3 knurledwhereby a person holding the camera may rotate the dials by digitalengagement.

The shutter speed indicator is xed to the hub t0 of a shutter speed cam3i which is journaled in the frame portion Hl. The central portion ofindicator 213 rests upon a Washer 32, and the indicator is held againstthe surface of the washer by a spring washer 33 interposed between thecam 3i and the lower surface of the supporting frame portion it.Similarly, the stop indicator 2| is fixed to the hub 35 of a stop cam 35which is journaled in the frame portion I6. The indicator 2i isseparated from the upper surface of the frame portion by a washer 31,and a spring washer' 38 is inserted between the cam 36 and the lowersurface of the frame portion l5. The earns lie horizontally beneath theframe portion it in the same plane, and each cam is rotated uponmovement of its associated indicator. As seen in Fig. 5, the outlines ofthe cams differ, the outlines of the cams being iixed by mathematicallyselecting variable radii which will produce desired results upon a lightintensity indicator 4G, as will presently appear.

The light intensity indicator dial 40 is set into an opening lll in theframe plate il. The dial 4B is rotatably mounted upon a reduced portion42 of a pinion gear hub 43 journaled in the raised portion it of theframe. rlhe light intensity dial is retained on the reduced portion 42by a reference dial 44 which is keyed to a further reduced portion 45 ofthe pinion hub so that the reference dial rests upon the shoulder formedbetween the portions 42 and 45. A screw 46 is screwed into the end ofthe reduced portion 45 to retain the reference dial 44 in position. Aspring washer il is positioned between the lower surface of the lightintensity dial 4G and a. shoulder on the hub 4t frictionally to retainthe light intensity dial against the reference dial whereby the lightintensity dial and the reference dial ordinarily move together as aunit. However, the reference dial is much smaller than the lightintensity dial, and the exposed portion of the latter may be manuallyengaged to slip the friction connection and move the light intensitydial with respect to the refe-rence dial. The light intensity dial isprovided with a plurality of indicia adjacent which are positioned wordsor other printed matter designating certain types of ligh conditionswhich are easily recognizable, for example, bright sun, hazy sun, cloudybright and cloudy dull. The indicia 50 extend to the outer edge oi thelight intensity dial for cooperation with subject indicia 5i on the xedframe plate Il. The subject indicia are marked according to thecharacter of the subject being photographed7 in easily recognizablefashion, for eX- ample, dark subject, average subject and light subject.Any operator should be able to recognize the four degrees of sunlightand the three types of subject and, by manipulation of the dials 2li andEl as will appear, place the proper index 5) in line with the properindex 5l.

On an opposed portion of the light intensity dial there are positioned aplurality of indicia 52, adjacent which are placed numerals indicatingemulsion speeds in accordance with the Weston nlm speed system. It isobvious that other types of nlm classification may be utilized, providedthe indicia are properly marked and spaced. The reference dial 44 isprovided with a pair of reference marks 53 and 54, for example, the mark53 being indicated as a summer reference mark and the mark 54 as aWinter reference mark. The positioning of the reference marks is suchthat the placing of an index 52 corresponding to the emulsion speed ofthe lm being used opposite one or the other of the marks 53 and 54, orin between the two, will correct the exposure meter for the existingseason of the year. It is apparent that because of the reduced diameterof the dial 44, shifting from winter to summer will displace the indicia50 to a considerable extent.

The reference marks 53 and 54 are herein illustrated as marked forseasonal, or angle of sun, correction, it is to be appreciated that thereference marks may likewise serve for correction of other variablefactors such as filters of various degrees of opacity.

In order that the positioning of the indicators 2G and 2i may bereflected in the position of the light intensity dial 40, integratingmechanisni is provided as follows. A graduated pivot St is nxed to acentral portion of the frame portion IB. A sector gear BI is Pivotallymounted upon the first step of the pivot 6D, the sector gear havingteeth which mesh with the teeth of a pinion t2 fixed to the hub 43. Acam follower tt is slidably mounted upon the lower surface of the sectorgear, the cam follower in the present embodiment being T-shaped andhaving cam engaging portions and 65 on its arms. The cam 3i has itshighest point underlying the slowest shutter speed index 22, and the cam36 has its highest point underlying the smallest stop index 23, the samebeing illustrated in Figs. 4 and 5. The lowest points of the camssimilarly underlie the fastest shutter speed index and the largest stopindex. Since each of the cams may be moved independently of the other,an iniinitely variable number of positions may be assumed by the camfollower as the portions 65 and are shifted about. In order to cause theshifting of the cam follower to rock the sector gear 6| about pivot 60,the cam follower is pivotally mounted upon the pivot (it and is slidablelongitudinally of the sector gear. This is preferably done by providinga slot 6? through which a reduced portion of the pivot tu projects, anda spaced slot 6B through which passes the stem portion of a guide 69iixed 'to the sector gear El. The slots 61 and S8 are longitudinallyaligned in the cam follower so that any pivotal movement of the camfollower causes pivotal movement of the sector gear t i. The camiollower is retained against the surface of the sector gear by theenlarged head of guide 69 and by a spring clip 'l0 retained in a groovein the end of the pivot 60. The cam follower is caused to bear againstboth cams by a pair of springs 1I tensioned between ears 'I2 on the armsof the cam follower and a spring anchoring bar 73 xed by screws 'i4 to aportion of the frame. As illustrated in Figs. 4 and 5, the cam followeris at such a position that the central teeth of the sector gear meshwith the pinion. From this position a large number of other positionsmay be assumed, such as that illustrated in Fig. 13, whereby the piniongear is rotated through arcs of movement reflecting the movements of theshutter speed and stop indicators. It is to be appreciated that the camfollower is herein illustrated as a T-shaped member, but that the shapethereof is unimportant; also, various other forms of sliding connectionsmay be provided between the cam follower and the sector gear; and thatin lieu of a sector gearY and pinion drive other mechanical expedientsmay be utilized whereby rocking of a member such as sector gear 5|causes movement of a light intensity indicator.

When the exposure meter isV utilized as a portion of a camera, theindicator 2| is connected to a diaphragm adjusting mechanism as setforth in Figs. 2 and 3 and, similarly, the shutter speed dial isconnected to a shutter speed adjusting mechanism such as illustrated inmy copending application, Serial No. 754,961, filed June 1'7, 1947, nowPatent No. 2,553,015, issued May 15, 1951, wherein a cam is illustratedas connected to a speed indicator dial and mechansim is shown which isaffected by the cam to regulate the speed of the shutter. Only so muchof the mechanism as necessary for an understanding thereof is hereinillustrated, and other forms of such mechanism may be substitutedtherefor.

In the illustrated form the cam 36 is fixed to a vertical shaft 80, thelower end of which is journaled in a fixed member 8| suitably mounted inthe camera. A pinion 82 on shaft 80 meshes with the teeth of a rack 8',one end of which is provided with a slot S5 through which extends thestem of a vertical guide pin 86 and the other end of which is providedwith a slot 31 through which extends the stem of a horizontal guide pin8B, the pins being mounted upon fixed supports 8S and S0 respectively,suitably mounted in the camera. As the shutter speed indicator dial isrotated, rack Si is shifted longitudinally. A vertically extendingportion of the rack 81| is provided with a lug 5| which projectsforwardly into a vertical slot 32 in an upwardly rising portion 9.1i ofa diaphragm connecting member 3G. The extremities of the member 36 arepivotally connected to arms 91 fixed to diaphragm adjusting rings 98rotatably mounted on inner portions of the lens barrel assemblies il andi2 and operatively connected to the iris diaphragme 89 in the usualmanner of such devices. rack 84 is moved longitudinally the connectingmember 96 is also moved longitudinally and is permitted to movevertically by reason of the crosshead connection comprising the lug 9|and slot 92. It will ce obvious from inspection of Fig. 2 that a singlecamera diaphragm adjusting ring could be operated by mechanism asillustrated and that any other suitable mechanism whereby rotation ofshaft 8B is translated into rotation of a diaphragm adjusting ring E8may be substituted therefor. In Fig. 2 it is also seen that the cam 3|is connected to a shaft |60 which, in turn, may be connected to anysuitable shutter speed regulating mechanism such as illustrated in theaforesaid copending application.

Figs. l5 and 16 illustrate the shutter blades, and Figs. 17 and 18illustrate the shutter speed regulating and controlling mechanism of theabove-identified Patent No. 2,553,015. The shutter blades comprise thinmetal sheetsy one such sheet being formed to provide a first shutterblade i and another such sheet being formed to provide a second shutterblade IH. IThe shutter blades are superimposed and guided bychannelforming members l |2 and I3 so as to move endwise across theinner extremities of the lens barrel assemblies. The channel-formingmembers are suitably attached to an interior frame and are centrallyopen (not shown) so that apertures in the shutter blades may admit lightto the iilm from the lenses when the shutter blades are released. T'hefirst shutter blade is provided with a pair of apertures ll which areadapted to cooperate with a second pair of apertures H in the secondshutter blade. By controlling the AS the portion of the frame.

time of release of one blade with respect to the other, the size of theapertures formed by overlapping portions of the apertures ill and I i5may be controlled to determine the shutter speed, as fully explained inthe aforesaid patent. The first shutter blade is provided with anelongated slot ||6 in which is positioned a shutter blade operatingspring ||1 having one end attached to the blade and the other endattached to a suitable The second shutter blade is provided with anelongated slot H8 in which is mounted a similar operating spring H9. Theshutter blades are adapted to be moved to the left to a set position atwhich they block passage of light through the lenses. For this purposethe first shutter blade is provided with a reset slot |23 and the secondshutter blade is provided with an aligned reset slot |2|, in which theremay be engaged a reset finger |22 at the end of a reset lever |23 havinga downwardly bent tab |24 engaged in a guide |25 formed on the member|13. The reset lever |23 is pivotally connected at |26 to a gear |21driven by a pinion |28 at the lower end of a reset knob shaft |23. Whenthe gear |21 is rotated through an operative cycle by the reset knob(not shown) at the end of shaft |29 the reset finger |22 moves to theleft and moves the shutter blades to their set position. The springs iI1 and H9 cause operative movement of the blades to released positionsat which they again block the passage of light.

1n order to control the release of the shutter blades, means areprovided comprising a lower edge notch |30 in the rst blade and anoverlapping, lower edge notch 53| in the second blade, and a slot |32 inthe rst blade and an overlapping slot |33 in the second blade. A firstshutter latch |34 pivotally mounted on a portion of the frame projectsinto the slots |32 and |33, and a second shutter latch |35 mounted onthe frame projects into the notches |3| and |32. The latches are urgedto remain in the positions illustrated by means of the springsassociated therewith, but may be forced to pivot clockwise, if releasedfrom engagement with holdingpawls, by the greater force oi the springsl1 and l i3. The first latch is adapted to be held in shutter-retainingposition by a primary shutter latch pawl |325, and the second latch isadapted to be held in shutter-retaining position by a secondary shutterlatch pawl |31. The primary shutter latch pawl |33 is pivotally mountedon the lower end of the shaft |00 and is urged toward latch-retainingposition, as seen in Fig. 18, by a mainspring |38. An extension of thepawl |36 is provided with a pin |39 which is engaged by a shoulder iflilon the reset lever |23 during the cycle of resetting the shutters so asto move the pawl to latch-retaining position against the force of spring|38. The pawl |33 is held in latching position by a pawl latching lever54|. rEhe latching lever |l| may be moved to release the pawl |36 bymovement of the manually actuated release lever |42 which has a portionof its right end engageable by manual release means (not shown). Aportion of the release lever |42 engages a tab irl@ on the latchinglever MI to move the latching lever to releasing position, permittingthe mainspring |38 to move the pawl |35 counterclockwise to release theprimary latch i3d. A pin |62 on the pawl |33 extends through an openingin a mounting plate for the described mechanism and is engaged by aportion of an escapement mechanism including a sector gear |45, wherebythe spring |38 drives the sector gear clockwise about its pivot. Thesector gear is pivotally and slidably connected to one portion of afloating lever |46 which has a fulcrum portion lill engageable with aportion of an adjustable timer cam |48 xed to the lower end of the shaft|03. The timer cam has portions or" different radii which may bepositioned in the path of movement of the fulcrum portion lill as thefloating lever |46 moves at a controlled speed as regulated by theescapement mechanism due to the force of the spring |38. When thefulcrum portion Ml engages the selected portion of the timer cam, a tailportion |49 of the floating lever is pivoted to move the latch pawl |37from holding engagement with the secondary latch l 35, such movementtension in the spring I@ which normally holds the latch pawl |31 inholding engagement. The interval of time between release of the primaryshutter latch |34 and the secondary shutter latch |35 is determined bythe adjusted position of the timer cam |43 corresponding to the settingof the shutter speed indicator 2D. Other details of the shuttercontrolling mechanism are more fully set forth and claimed in theabove-identied Patent No. 2,553,015.

It is preferred that the rotation of cams 3| and 36 and of the mechanismconnected thereto be limited so as to protect the various associatedmechanisms. In order to limit movement thereof, any suitable abutmentmeans may be provided such as the pins ll extending upwardly from theframe portion i6 into arcuate slots It?! in the lower surfaces of theindicator dials 2G and 2|.

Figs. 13 and 14C illustrate a slight modification wherein the frameportion I6 and the connected rear wall I3 comprise a casing, the lower'edge of which is slightly below the spring attaching bar |55corresponding to the bar 'I3 in the nrst modification. A closure plateti bridges the lower edges of the vertical walls to protect themechanism, the same being mounted on the frame as by means of screwsll'l. In this modification the lower ends of the shafts upon which thecams 3| and 3S are mounted are journaled in a pair of arms its formedintegrally with the bar |05. Aside from the substitution of the modinedform of spring attaching bar and the journaling of the cam shaftstherein, the mechanism remains exactly the same and functions exactlythe same as that previously illustrated.

Operation n Figs. 1 and 2 the mechanism is illustrated at anintermediate position wherein the shutter speed has been set at 1/5 of asecond, the di aphragm has been set at stop 6.3, and the light intensitydial has been adjusted with respect to the reference dial for properselection of values when using a nlm of speed emulsion factor in thesummertime, or of factor in the winter-- time. In Figs. i and 5 theshutter speed has been slowed down to 6 of a second, the diaphragm hasbeen closed to stop l5, and the light intensity dial has been shiftedwith respect to the reference dial to indicate that a film of emulsionspeed factor 8 is being used in the summertime. The bright sun lightindex 50 being opposite the light subject index 5| indicates that atthis stop and speed the only properly exposed picture which may be takenunder the existing conditions is of a light subject under bright sun.

In Fig. 7 the diaphragm has been opened wide to stop 3.5, all otherfactors remaining the same as in Fig. 4, and the position of the lightintensity dial indicates that at this slow speed and with a wide-openshutter only a dark subject may be properly photographed, and that onlyon a cloudy, dull day. In Fig. 8, with all other factors remaining thesame, the shutter speed has been increased to V of a second and theposition of the light intensity dial indicates that a light subject maybe photographed only under a hazy sun or a dark subject under a brightsun. Therefore, if the speed of movement of the object or the desires ofthe photographer demand retention of the high shutter speed at to@ of asecond, and the subject is light and the sun bright, the diaphragmaperture must be decreased to stop 5.6 as indicated in Fig. 9. In Fig.l0, under the same conditions are expressed with regard to Fig. 9,

but with the picture being taken in the middle of the winter, the lightintensity dial has been shifted with respect to the reference dial toplace the film emulsion speed number 8 opposite the winter referencemark. The position of the light intensity dial now is such as to showthat even the lightest subject under the brightest sun at this season ofthe year cannot be photographed properly. One of two things could bedone:

: namely, to decrease the shutter speed until bright sun lines up withlight subject or, as is indicated in Fig. 1l, to open the shutter tostop 4, thus lining up the bright sun and light subject indices. In Fig.12 an extremely fast nlm of speed value l0() is being used in thewintertime under the same conditions as previously expressed for slowspeed film in Fig. ll. Shifting the light intensity dial with respect tothe reference dial, as illustrated in Fig. l2, so shifts the indicia 50with respect to the indicia 5l as to indicate that one or the other ofthe cams must be adjusted. It will be apparent that under bright sunwhen photographing alight subject the only cam which can be adjusted tobring about proper alignment is the stop cam 36. Rotation of theindicator 2| until the bright sun and light subject indicia are alignedbrings the indicator 2| to a position wherein the pointer 25 is midwaybetween the stop values 1l and 16. An innite number of correctly pairedshutter speeds and stop values may be thus selected within the rangespermitted by the character of the subject and the intensity of the sun,each of which infinite number of Values may be altered to compensate forother factors such as the nlm emulsion speed, the season of the year,the type of filter being used, and the like.

The operation of the integrating mechanism is illustrated in Figs. 5 and13 wherein it is seen that as one or the other, or both, of cams 3| and38 are shifted the cam follower is shifted either longitudinally withrespect to the sector gear or pivotally about the pivot 6i), or acombination of such movements, the net result being pivotal movement ofthe sector gear and pinion 62 whereby the light intensity dial is movedin accordance with the positioning of the two cams.

l'aving illustrated and described preferred embodiments of theinvention, it will be apparent to those skilled in the art that theinvention permits oi modification in arrangement and detail. claim as myinvention all such modincations as come within the true spirit and scopeof the appended claims.

I claim:

l. A camera having a iight admitting orifice, a shutter movablyassociated with said orifice to control the passage of lighttherethrough, means to adjust the size of said orince including amanually engageable stop indicator mounted on the exterior of thecamera, iris means in said camera and means operatively connecting saidiris means to said stop indicator, means to adjust the speed of movementof said shutter including a manually engageable shutter speed indicatormounted on the exterior of the camera adjacent said stop indicator,shutter speed controlling means in said camera comprising an adjustableelement, and means operatively connecting said adjustable element tosaid shutter speed indicator, means to indicate the proper selection oforice size and shutter speed for the existing intensity of light and thetype of subject being photographed comprising a light intensityindicator mounted on the exterior of the camera adjacent said stop andshutter speed indicators, and operating means for said light intensityindicator comprising a first cam connected to said stop indicator, asecond cam connected to said shutter speed indicator, a single rigid camfollower having spaced portions ea-ch bearing against one of said cams,resilient means biasing said portions into engagement with therespective cams, and integrating means operatively associated with saidcam follower and said light intensity indicator to translate movement ofsaid cams into movement of said light intensity indicator.

2. A camera having a light admitting orice, a shutter movably associatedwith said orice to control the passage of light therethrough, means toadjust the size of said orice including a manually engageable stopindicator mounted on the exterior of the camera, iris means in saidcamera and means operatively connecting said iris means to said stopindicator, means to adjust the speed of movement of said shutterincluding a manually engageable shutter speed indicator mounted on theexterior of the camera adjacent said stop indicator, shutter speedcontrolling means in said camera comprising an adjustable element, andmeans operatively connecting said adjustable element to said shutterspeed indicator, means to indicate the proper selection of orice sizeand shutter speed for the existing intensity of light and the type ofsubject being photographed comprising a light intensity indicatormounted on the exterior of the camera adjacent said stop and shutterspeed indicators, a shaft connected to said light intensity indicator, arst cam connected to said stop indicator, a second cam connected to saidshutter speed indicator, 'and means to rotate said shaft comprising asingle rigid cam follower having spaced portions each bearing againstone of said cams, spring means urging said portions against therespective cams, and integrating means comprising a sector gearpivotally mounted adjacent said cams, a pinion xed to said shaft andmeshing with said sector gear, and means slidably connecting said camfollower to said sector gear for movement along a line passing throughthe pivotal axis thereof whereby movements of said cams are integratedand translated to said light intensity indicator.

References Cited in the le of this patent UNITED STATES PATENTS Number

